Electric generating system



July 2l, 1925.

R. PURINTON ET Al. 1546"865 ELECTRIC GENERATING SYSTEM Filed May 22. 1923 cui 0f? Ya/ve 7 Governor lE m i W////////////////////////////////// l///l/ van Inventors; Ralph B. Puv'nbo'n, ClaudewPlnce,

Their Attorneg Patented July 2l, 1925,

UNITED STATES PMENT OFFICE.

RALPH B. PURINTON `AND CLAUDE W. PLACE, OF CHICAGO, ILLINOIS, ASSIGNOIRS TO GENERAL ELECTRIC COMPANY, ,A CORPORATION OF NEW YORK- ELncTnrc GENERATING SYSTEM.

T0 all if/'zof/n. t may concerm' Be it known that we, RALPH B; PURIN'roN and CLAUDE 1V. Praxen, citizensof the United States, residing at Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Electric GeneratingSystems, of which the following is a specification.

Our invention relates to electric generatingsystems and while applicable to manually or automatically controlled generating plants is of particular use in automatic hydro-electric generating plants. An object. of our invention is to provide in such a sys'- teni for maintaining closed during a momentary reduction or failure in the line voltage themain switch'by which the generator or generators are connected to the line. Anotherobject is to provide for the opening of the switch after al failure of the line voltage shall have continued for a predetermined length of time or to provide for opening the switch in the event that such failure in voltagekor a reduction of the same below a predetermined value recurs at too frequent intervals. A further object is the provision of a source of energy which shall be .always available for opening the main switch after the line voltage has completely failed.

Our invention will be better understood by reference to the accompanying specification and drawing and its scope will be pointed out in the appended claims.

Fig. 1 is a cross section of a cell showing an oil switch therein and a part of the operating mechanism'therefor, the switch being shown in its closed position; Fig. 2 is a cross sectional view taken on the line 2-2 and looking in the direction of the arrows, and Fig. 3 is a circuit diagram, thevarious switches beingl shown in open circuit position. Y y

Referring now tothe drawing, an oil r switch denoted generally by reference number 1 is `shown enclosed -by a cell 2 upon which is mountedthe main operating lever 3 connected to the switch by the operating rod i and operated by the toggle links 5 and rod 6. Rod`6 is pivoted to lever 7 which lever is held in the position illus- Application led May 22, 192.3 Serial NQ. 640,705.

trated by Fig. 1, which corresponds to closed kcircuit position of the Switch, by means of vgovernor (not shown) for the water wheel also provides the operating force for closing the main switch and for controlling the tripping open of the same. Referring now to Fig. 2, the frame 11 has depending therefrom a spacer 12 to which is attached a cylinder 13 in which slides a piston 14 carrying a piston rod 15. The piston rod 15 in ascendlng engages the'lever 7 to rotate it in aclockwise direction, thereby lifting the rod 4to close the main switch. A coil spring 16 insures the return of the piston 14 to its 'normal position. The toggle links 9 may be caused to buckle and thereby to trip open the main switch either by the energization of the usual trip solenoid 17 operating through the rod 18 or by an oil controlled device now to be described. This device comprises a cylinder 20 having walls integral with the spacer12, through which cylinder slides a piston 21 carrying a piston rod 22. The rod 22 engages rod 18 and slides through a head 23 closing' the upper end of the cylinder. A coil spring24 arranged in the cylinder 20 operates to raise thepiston 21 and rod 22 to trip open the main switch. A small passage 25 is shown connecting the cylinders 2O and 13 whereby any oil that passes the piston 21 may escape into the larger cylinder and this oil together with anyoil that passes the piston 14 may escape through the passage 26 into pipe 27. lFor 'controlling the admission of oil into the cylinder 13 and its exit therefrom an electro-magnetically controlledvalve is provided. For Ythis valve a pair of spaced valve seats is formed on a lateral extension 29r of the cylinder 13 and the space between the two seats is lconnected by a Vpassage 30 with the 'cylinder 13. A'frame member 31 mounted upon the lateral extension 29 has the lower valve seat to control-the' escape of oil from the cylinder 13 intolth'e'exhaustpipe V 37 and thence to the sump. Mounted on the top of the member 31isfa-nfelectromagnetcomprising a solenoid 39 and a plunger 40, at the lowerendl oa'i'which is a weight A valve rod 'l2 sliding in anintermediate portion yof the frame member 31" supports the plunger '4Q *and weightlll* andhas -a valve 4f3at lits lower end whi'ch `controls a passage leading .from/space' abovel the plunger 32 to a pipe lili connecting witlr theexhaustpipe 37'. 'A' compression' spring 45 -is arranged above the-plunger 32:to urge the same down against'the'oilfpressure. The piston21 is normallydepressedf by oil pressure admitted through pipev 53fso-that the Kspring' 24 is h'eld. conipressed.' Any oil that escapes past the head =23"may=i`ndf itis way back into'the cylinderV 13' throughi a small opening 46" and the openingffor theL pistoni rod rl5, A' yswitch lfshowndiagrammatically in 3Jas a back contacten the mai-n "switchismounted on the'lfraine 12to-be opera-ted by lever'7 and is connectedy iirseries with the solenoid 39]-Y ltserves to holdthissolenoid open' circuited while-the main'switeh is closed.`

The valves controlled bythe solenoidi'39 admit oil to and'releaseiit from the cylinder l3f but ffor'varyying the lpressure in the=cylinder 20?, whereby' under proper conditions the nainlvswitcli may be tripped out, anf'addi? tional solenoid` operated valve, commonly termed cut-olf valve', I is employed which will now'be*described;I 'This valve as a whole islsimilar'inf'construction tof that just defscribed with the; exceptiomthat it has "a sin glel sea-t with which" thel valfve 50 cooperates to control tlfre flow of oilflfrom thepipe 451, leading from -anpoil' pressure-tan-lr, towthe pipe 52( Frompipe 52? onefbranch-pipe' 53 lead-s to cylinder `2O' and tothe valve 33 while another branch 54 leads tol a governor '(not show-n) such V'as that commonly usedin systems of `this types Th'e-l present f valve like that previouslyT ydescribed 'has 1 a: casing i or {ramal-'i5 ormingaseat or'thevalve 50 and has a' cylindrical portion in which' a'piston 56"'fits' :somewhat loosely,` being' urged @down bya spri1`igi57.` l-r'fva'lve'y controls the Vflow ofoil from they cylindrical lportion of the casingfto a pipe connecting withr the sump tli'rougli 'pipe 377:2 Resting upon the valve stem: off this va'lwer iis a plunger 68 carrying a xweight t69,'the plunger and weight I'being yadapted -r-tobe litted f solenoidl,

In the normal operation of the plant, the solenoid 61 remains energized thereby permitting the oil pressure to hold Yopen valves 58 and 50. VVhilethe construction and opi eration ofthezvalves 33 and 50l together with the mechanism for controlling the same have necessarily been described in detail, the specic construction othese valves, andtheir respective controlling mechanisms form no part of the present invention.

ln Fig'. Vwwe have shown a circuit diagram which illustrates a very simple manner of connecting the above described apparatus. For convenience the apparatus is shown connected to a single phase` transmissionline comprising con'ductorsA-and and, for the sake 'ofrsimplicityg connections are'inade directly therewith without fthe use ofthe usual transformers. The single switchV Gil'lnaybe consideredfias representative-of =a 'number' of switchesfseverally responsive to various corr ditions affecting thel operation of `ali-:automatichydro-electric station, such for'. eX- ainp'le as thef temperature ovf'ther'bearings, the=strength of the'generator` field current, the level oiwaterin'the';orebay,f eter. A switch -65 will bef. closed' whencthevgenerator has reached nearly@synchronous speed. This switch may bel afrcentrifuga'l :switch set= to f close -when the .generatorV speed:l :reaches 95% oft synchronousv speed., The latch device shown at lrel'aresents diagra-mmatically the toggles 8I andl 9 by whichthe main switch l is held: closed@connecting/'the' generator;- G

tothe linefwbut which. kmay betripped open either f byV -thezy solenoid 17 f in fresponse tovv an overload when switch 67V isf closed or vby the raising odi i the Apiston-',121 infresponse -to'fa predetermined rednctionnin ,oil pressure;

The operation oiithe above+describedVa=p paratusfis--in lpart as `follows t Assuming theV plant to: becnr normal operation :and: te be delivering energy -tolthefline, thevarious switches represented as a whole' by switch r64- lwill'be closed andl thev solenoid 6l? accordlenergized@Valve 58'fbeing allowed to open,` oil'runder pressure'rom-@the :pressure tank holdsthey piston 56f raised and. valve 59 opencwhereby oilnisl supplied to= the governorrt'o the' cylinder 20'and to-:valveV 33. 'Aicertain .amount of 'oil constantly escapes past the `piston` 563 baokxtoz-the sump' and likewise l a certain amount escapes "through they governor; v The inain'lswiteh?` 1: being closed, the solenoidt39F'is opencircuited `by ther switch 4582 so :that valve 43' remains closed. The escape of oil which leaks past the plungerf32'zbeing:thereby cut oil, the combined' oil and. spring, pressure en: the top ot theplunger causesvtheivalve33 to remain closedgi Dueto the connection offthe cylinderz29wwith the -pipe l52 vthe pressure or oil in .this cylinder maintains -therpiston 21 zde.- pressed compressing ther spring 24. Should now a naonientaryrednction occur in@ the 'line voltage, sometimes termed a dip in the voltage, as might result for example from the throwing in of a heavy load or from a lightning discharge, the valve '58 controlled by the solenoid 6l may momentarily close. However', before the valvek 50 will close a certa-in quantity of oil must leali past the plunger 56. Moreover, after the valve 50 has seated, pressure in the pipe 52 and connecting pipes will be reduced only to the extent that the oil escapes through the governor. A certain amount of time is therefore required after the controlling solenoid 61 has permitted the valve 58 to close before the oil pressure in the cylinder' 20 will be suliiciently reduced to cause the rod 18 to trip open the main switch. It is to be noted that the force for actuating the trip in this case is that furnished by the coil spring 2li which previously had been compressed and so maintained by the oil pressure. It will therefore be evident that even though the line voltage should fail completely and should the water wheel be shut down there is always a reliable source of energy available for tripping out the main switch.

The apparatus devised by us is of particular value in the event that the line voltage is at the critical value when the automatic station is thrown on the line in starting. As stated in the description above, the centrifugal switch which controls the switch 65 is usually set to cause the generator to be thrown on the line when the speed is approximately 95% of synchronous speed. lVhere electromagnet devices responsive to line voltage are employed to trip out the main switch, a hunting or pumping action often follows due to the repeated tripping out of the main switch resulting from the additional line drop produced each time the generator is thrown on the line. The trip controlling mechanism which we have disclosed herein, however, permits the generator to remain on the line sufficiently long to be brought up to full synchronous speed and to supply energy thereto.

Should the reduction or failure of line voltage occur intermittently such as might result from a swinging short circuit the repeated reduction in oil pressure will, after it has continued for a reasonable length of time, become sufficient to cause a tripping out of the main switch, however, if the cause of the trouble is removed and the line voltage resumes its normal steady value before that time no tripping of the switch will ocour.

In starting the automatic station, the closing of the switch 65 which as stated above, may be speed controlled, energizes the solenoid 39 to ope-n valve 4-3. The pressure of oil then lifts the piston 32 opening the valve 33 and closing valve 35. The piston ll raises and through the. levers, rods and links shown in Fig. 1 closesthe main switch l-. As the switch closes it opens switch 48 *thatV leaks past the piston 32 now moves valve733 to closed position and opens the eX- haust valve 35 to permit the return of piston 14.

While we have described only one embodiment of our invention, we do not wish to be limited to the particular form shown and described as it will bcl apparent that many modifications therein may be made without departing from the scope of our invention as set forth in the appended claims.

lVhat we claim as new and desire to secure by Letters Patent of the United States, is:

l. In a system comprising a generator, a line adapted to be supplied thereby and a switch for controlling the connection between said generator and line, fluid pressure controlled mechanism responsive to a failure in the line voltage for tripping open said switch, and a normally stressed resilient member for actuating said mechanism.

2. In a. system comprising a generator, a, line adapted to be supplied thereby and aswitch for controlling the connection between said generator and line, fluid pressure controlled means for tripping open said switch, and means responsive to a predetermined reduction in line voltage for varying said fluid pressure.

3. In a system comprising a generator, a line adapted to be supplied thereby and a switch for controlling the connection between said generator and line, a trip for said switch, a resilient member for actuating said trip, fluid pressure means for restraining the operation of said resilient member, and means responsive to the voltage condition of said line for releasing said fluid pressure at predetermined rate.

4. In a system comprising agenerator, a line adapted to be supplied thereby and a switch for controlling the connection between said generator and line, fluid pressure controlled means for tripping said switch upon a predetermined reduction in pressure of said fluid, and means responsive to a teinporary drop in the volt-age of said line for causing a delayed reduction in said pressure followed by a subsequent restoration of said pressure.

5. In a system comprising a generator, a line adapted to be supplied thereby and a switch for controlling the connection between said generator and line, a spring operated trip for said switch, fluid pressure means for preventing the operation of said trip, means comprising a valve for slowly reducing they pressure of said fluid, and an electromagnet responsive to the line voltage for controlling said valve.

l la) f 6;. In a: syste-n1 ofthe eharacter .cleseBibecL `of said main'swtch for. opening Lthe circuit main, switch, AHuid operated. actuating of said .electromagnetic means; Y means' tlieiefe-lf, n, souiee of fiuidf pressule, In; Witness whereof, We have hereuntoV set 10 af Valve: for aidlnittingy fluid? pressure JGhere.- our handsl this 19th deyrof M2915 1923. 5 :from te*A said actuating means, eleetpomagv Y v nete mea-ns for controlling said valve, and RALPH B. PURIN'ION,` a, Switch responsive to the closing nfiovellell' CLAUDENV. PLACE.y 

